• Restorative Dentistry and Endodontics
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• v.38 no.3
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• pp.154-159
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• 2013

Objectives: The aim of this study was to compare the cleaning efficacy of different final irrigation regimens in canal and isthmus of mandibular molars, and to evaluate the influence of related variables on cleaning efficacy of the irrigation systems. Materials and Methods: Mesial root canals from 60 mandibular molars were prepared and divided into 4 experimental groups according to the final irrigation technique: Group C, syringe irrigation; Group U, ultrasonics activation; Group SC, VPro StreamClean irrigation; Group EV, EndoVac irrigation. Cross-sections at 1, 3 and 5 mm levels from the apex were examined to calculate remaining debris area in the canal and isthmus spaces. Statistical analysis was completed by using Kruskal-Wallis test and Mann-Whitney U test for comparison among groups, and multivariate linear analysis to identify the significant variables (regular replenishment of irrigant, vapor lock management, and ultrasonic activation of irrigant) affecting the cleaning efficacy of the experimental groups. Results: Group SC and EV showed significantly higher canal cleanliness values than group C and U at 1 mm level (p < 0.05), and higher isthmus cleanliness values than group U at 3 mm and all levels of group C (p < 0.05). Multivariate linear regression analysis demonstrated that all variables had independent positive correlation at 1 mm level of canal and at all levels of isthmus with statistical significances. Conclusions: Both VPro StreamClean and EndoVac system showed favorable result as final irrigation regimens for cleaning debris in the complicated root canal system having curved canal and/or isthmus. The debridement of the isthmi significantly depends on the variables rather than the canals.

• Journal of Radiation Protection and Research
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• v.40 no.2
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• pp.101-109
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• 2015

Alpha spectrometry is typically used for the assessment of uranium particle concentrations and its accuracy can be directly related to the accuracy in which the radiochemical pre-treatment is conducted. Ashing and alkali fusion methods are typically used but the ashing method requires longer analysis time and the alkali fusion method is extremely costly. Therefore, a new pre-treatment method using ultrasonic cleaning was developed and its experimental result was compared against the two conventional methods in terms of pre-treatment time, convenience, cost, and recovery rate of a target material. The results that were obtained by the conventional methods(ashing and alkali fusion) and the new method were compared. Consequently, even though the shorter pre-treatment time was required, the new technique showed almost same recovery rate comparing with two conventional methods. The new method was also featured by its relatively lower cost and a simpler process than two conventional methods.

• Journal of the Korean Society for Nondestructive Testing
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• v.27 no.3
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• pp.224-230
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• 2007

This work is aimed to explore a possibility of using the generalized Lamb waves for nondestructive evaluation of the bonding quality of layered substrates. For this purpose, we prepared two sets of specimens with imperfect bonding at their interfaces; 1) TiN-coated specimens with various wear conditions, and 2) CVD diamond specimens with various cleaning conditions. A dispersion simulation performed for layered substrates with imperfect interfaces are carried out to get the characteristics of dispersion curves that can be used for bonding quality evaluation. Then the characteristics of dispersion curves of the fabricated specimens are experimentally determined by use of an ultrasonic backward radiation measurement technique. The results obtained in the present study show that the lowest velocity mode (Rayleigh-like) of the generalized Lamb waves are sensitively affected by the bonding quality. Therefore, the generalized Lamb waves can be applied for nondestructive evaluation of imperfect bonding quality in various layered substrates.

• Textile Coloration and Finishing
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• v.23 no.4
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• pp.290-297
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• 2011

In this study, the possibility of the practical development of highly sensitive clothing textiles using fibrillated wool fibers were considered by determining the dyeability, the physical and mechanical properties of fibrillated wool fibers treated under strong acid and high temperature ultrasonic wave irradation and they were compared with those of untreated wool fibers. The color strengths of the dyed fibrillated wool fabrics increased by the acid metal complex dyes contrary to the untreated wool fabrics, and color fastness properties to rubbing, light, and dry cleaning were excellent, similar to those of the untreated wool fabrics. The tensile strengths of fibrillated wool fabrics were also kept after the dyeing. Moreover, the Numeri, Fukurami, and THV of the fibrillated wool fabrics were better than those of the untreated wool fabrics.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.9
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• pp.36-47
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• 1999

Three-way catalyst converter, cleaning up the exhaust gas contamination of SI engine, has the best efficiency when A/F ratio is near the stoichiometry . The feedback control using oxygen sensors in the exhaust manifold has limits caused by the system delays. So the accurate measurement of air flow rate to an engine is essential to control the fuel injection rate especially on transient condition like the rapid throttle opening and closing. To measure the rapid change of flow rates. the air flow meter for the engine requires quick response, flow reversal detection, and linearity . Tjhe proposed integration type air flow meter (IFM), composed of an ultrasonic flow meter with an integration circuit, has significantly improved the measurement accuracy of air mass inducted through the throttle body. The proposed control method estimated the air mass at the cylinder port using the measured air mass at the throttle . For the fuel dynamic model, the two constant fuel model is introduced . The control parameters from air and fuel dynamics are tuned to minimize the excursion of the air fuel ratio. As a result A/F ratio excursion can be reduced within 5% when throttle rapidly opens and closes at the various engine conditions.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.2
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• pp.1-8
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• 2020

While dental clinics still use the ultrasonic scaling/surgery tool for teeth scaling and cleaning the tool's use is expanding steadily to include treatment of damaged teeth and bone tissue. In this study, a handpiece moving system (HMS) was developed to evaluate bone scaling and cutting in the field of dentistry. The HMS, through a scaling test of bone using a scaler tip, it was able to identify surface damage. Additionally, a thermos-graphic camera was used to observe the temperature distribution that occurred during the bone scaling and cutting process. Consequently, we found that increasing the working load increased the amount of surface damage. Changes in temperature distribution occurred slowly and were maintained within safety bounds for 10 minutes. Going forward, we will compare the HMS performance on scaling and cutting with other devices.

• The Journal of the Acoustical Society of Korea
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• v.16 no.5
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• pp.12-17
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• 1997

In this work, we developed a new type ultrasonic dehumidifier with piezoelectric ceramics, which and efficiently repel waterdrops on outdoor glass plates exposed to raindrops. Through finite element analysis of a certain type of glass plates to analyze its dynamic behavior, the structure of the ultrasonic device we determined to get the optimal performance. A supplemental metal plate was attached to the glass plate for uniform cleaning. Based on the theoretical results, experimental samples were fabricated and evaluated with various dimensions of the glass plate and the piezoceramic vibrator. Driving circuit for the dehumidifier made use of the frequency sweeping technique to keep track of the resonant frequency of the glass plate that was variant with environmental conditions.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.2
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• pp.191-196
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• 2023

In this paper, for the application of ultrasonic cleaners for cleaning dentures and transparent braces, Pb(Mn_1/3Nb_2/3)O₃-Pb(Ni_1/3 Nb_2/3)O₃-Pb(Zr,Ti)O₃ [PMN-PNN-PZT] system ceramics were manufactured and their dielectric and piezoelectric properties were investigated. Overall the best properties suitable for the device applications such as ultrasonic cleaner were obtained from the ceramics sintered at 920℃: bulk density of 7.8 g/cm³, the dielectric constant (ε_r) of 1,689, piezoelectric charge constant (d₃₃) of 433 pC/N, planar electromechanical coupling factor (k_p) of 0.64, mechanical quality factor (Qm) of 835, S₁₁^E of 13.37 (10^-12 N/m²), and Curie temperature of 315℃ By using the physical properties of this composition, the ultrasonic cleaner was designed and simulated using the commercial ATILA software. For the three-layered ceramics with the dimension of 25 mm × 25 mm × 2.5mm, an excellent displacement of 8.998 10^-3 m) and the sound pressure of 147.68 dB were recorded.

• Journal of Korean Society of Disaster and Security
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• v.17 no.1
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• pp.27-35
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• 2024

This paper presents experimental research results to evaluate the applicability of chemical neutralization reaction and ultrasonic wave to remove cement paste and mortar attached to the surface of recycled aggregate. In order to derive optimal ultrasonic cleaning efficiency and chemical neutralization reaction, experiments were conducted using variables such as ultrasonic frequency and type of chemical solution. As a result, the optimal frequency was found to be 24 kHz, and immersion in a 15% hydrochloric acid solution for 30 minutes of stimulation showed the highest efficiency. In addition, the specific gravity, absorption rate, and wear rate of the quality-improved recycled coarse aggregate were similar to those of general aggregate and were found to satisfy all KS F 2527 standards. Therefore, it is believed that the recycled aggregate whose quality has been improved through the method proposed in this study can be used for concrete.

• The Journal of the Korean dental association
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• v.53 no.10
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• pp.743-750
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• 2015

Objectives: This study compared the mechanical efficacy of sonic activated and passive ultrasonic irrigation for removing intracanal medicament from a simulated root canal under controlled conditions. Materials and Methods: Thirty simulated root canal in resin blocks were randomly divided into 3-groups. The canals were enlarged using ProTaper files and K3XF (#30/0.06). After cleaning and drying, canals were filled with Calcipex. Overfilled materials were wiped out and measured their weight to the unit of 1/10mg. After one week storage in 100% humidity $37^{\circ}C$ temperature, canals were irrigated using 20mL of saline with one of following methods according to the designated groups (n = 10). For group-NI, 30-gauge nickel-titanium irrigation needle was used. During irrigation with every 5mL, needle was moved in-and-out with 4-mm amplitudes. EndoActivator and ultrasonic tip were used for group-EA and group-UT respectively for 20 seconds after every 5mL irrigation using needle. Then the weight was measured again to calculate the weight of residual remnants. The data were analyzed by one-way ANOVA and Duncan's post-hoc test at a significance level of 95%. Results: The weight of the residual medicaments were $3.62{\pm}0.81mg$, $2.84{\pm}0.28mg$, and $2.73{\pm}0.90mg$ for group-NI, -EA, and -UT, respectively. Group-EA and group-UT had no significant differences to remove intracanal medicament and left significantly less amount of paste than group-NI (p < 0.05). Conclusions: Under the controlled conditions of this study, the sonic activation and PUI have similar mechanical efficacy for removing intracanal medicament.